Adhesive for connection of circuit member and semiconductor device using the same

ABSTRACT

An adhesive for connecting circuit members, which is interposed between a semiconductor chip having protruding connecting terminals and a board having wiring patterns formed thereon for electrically connecting the connecting terminals and the wiring patterns facing each other and bonding the semiconductor chip and the board by applying pressure/heat, containing a resin composition containing a thermoplastic resin, a crosslinkable resin and a hardening agent for forming a crosslink structure of the crosslinkable resin; and composite oxide particles dispersed in the resin composition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation Application of PCT application No.PCT/JP2008/050140, filed on Jan. 9, 2008.

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2007-002308, filed Jan. 10, 2007,the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an adhesive for connecting circuitmembers and a semiconductor device using the same. More specifically,the present invention relates to a circuit-member connecting adhesivefor connecting semiconductor elements to a circuit board in accordancewith a face-down bonding system with application of heat and pressure, acircuit-member connecting adhesive (circuit-member connectinganisotropic conductive adhesive) having conductive particles dispersedtherein and a semiconductor device using these.

BACKGROUND ART

Generally, as a system for directly mounting semiconductor chips(hereinafter sometimes simply referred to “chips”) on a circuit board inaccordance with a face-down bonding system, a system in which solderbumps are formed on electrode portions of semiconductor chips, which areconnected to a circuit board by soldering, and a method in which aconductive adhesive is applied to protruding electrodes provided tosemiconductor chips for electrically connecting to circuit-boardelectrodes, are known.

These systems have problems. When a chip and a board are exposed tovarious environments, stress is produced in the connection interfaceascribed to a difference in thermal expansion coefficient between thechip and the board to be connected, with the result that connectionreliability decreases. Therefore, in order to reduce the stress in theconnection interface, a system for filling the gap between the chip andthe board generally with an underfill material such as an epoxy resinhas been studied.

As a filling system with the underfill material, mention may be made ofa system in which a chip and a board are connected and thereafter alow-viscosity liquid resin is injected and a system in which anunderfill material is placed on a board and then a chip is mounted. Inthe meantime, as a method in which an underfill material is previouslyplaced on a board and then a chip is mounted, a method of applying aliquid resin and a method of attaching a resin film are known.

However, in the case of applying a liquid resin, it is difficult toaccurately control the application amount by a dispenser. In the contextof a recent tendency toward thin-film chip, the resin, if excessivelyapplied, runs off from a chip in a bonding process, moves up along theside surface of the chip and contaminates a bonding tool. Because ofthis, a tool washing step must be added, complicating a process at thetime of a large-scale production.

Alternatively, in the case of bonding a resin film, it is easy to supplyan optimum amount of resin by controlling the thickness of the resin;however, when the film is bonded to a board, a step of bonding the filmcalled a provisional pressure-bonding step is required. In theprovisional pressure-bonding step, a reel tape having slits at theintervals larger than the width of a target chip is used. The adhesivepresent on the base material of the reel tape is cut in half dependingupon the size of the chip and bonded to the board by thermocompressionbonding at such a temperature that an adhesive does not react.

Since the accuracy of supplying the film to a chip mounting position islow, generally a larger film than a chip size is bonded in theprovisional pressure-bonding in order to keep yield. Accordingly, enoughdistance is required to an adjacent component, impeding high-densitypackaging. On the other hand, thin-width reel processing dealing withmicrochips, etc. is difficult. It is still necessary to bond a largerfilm than a chip size to deal with this case. An extra mounting area isrequired.

In the context, a method for supplying the same-size adhesive as a chipsize is proposed. In this method, an adhesive is supplied in the stageof a wafer and then processed simultaneously with chips by dicing or thelike to obtain chips attached with the adhesive (see, for example,Patent Documents 1, 2).

-   Patent Document 1: Japanese Patent No. 2833111-   Patent Document 2: Japanese Patent Application Laid-Open No.    2006-049482

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

However, the preset underfill method on a wafer so far proposed has thefollowing problems and not commonly used in the market. For example, inthe method of Patent Document 1, an adhesive film is attached to a waferand thereafter the wafer is diced into discrete pieces to obtain chipswith the adhesive film.

According to this method, a wafer/adhesive/separator laminate isprepared and cut, and thereafter, the separator is peeled off to obtainchips attached with an adhesive. However, this method has a problem inthat the adhesive and the separator are dissociated in cutting thelaminate, with the result that discrete semiconductor chips scatter andrun off.

Second, Patent Document 2 provides a method concerning a waferprocessing tape having a sticky layer and an adhesive layer in which awafer is bonded to a wafer processing tape and diced, and then, discretechips picked up are connected to a board by flip-chip.

However, generally in flip-chip mounting, terminals called bumps formedon the circuit surface of a chip are connected to the correspondingterminals on a board. For this purpose, an alignment mark on the chip isaligned with an alignment mark on the board by a flip-chip bonder andthen bonded. However, when an adhesive is applied on the circuit surfaceof a chip, the adhesive covers the alignment mark of the circuitsurface, impeding alignment. This is a problem. However, Patent Document2 does not provide any solution to deal with this problem.

On the other hand, a technique for obtaining transparency of a resin isdescribed in the specification of Japanese Patent No. 3408301. That isan anisotropic conductive film containing conductive particles andtransparent glass particles dispersed in an insulating adhesive and anadhesive. However, since the glass particles are amorphous and thus havea large linear expansion coefficient, it is thus difficult to attain alow linear expansion coefficient required as a property after theflip-chip mounting.

In the context, an object of the present invention is to provide acircuit-member connecting adhesive, which has excellent adhesiveness toa wafer in an unhardened state, through which an alignment mark providedto the wafer is highly recognizable, and has excellent adhesiveness andconnection reliability between a chip and a board in a hardened state,and provide a semiconductor device using the same.

Means for Solving Problem

The present invention relates to the following items.

(1) An adhesive for connecting circuit members, which is interposedbetween a semiconductor chip having protruding connecting terminals anda board having wiring patterns formed thereon for electricallyconnecting the connecting terminals and the wiring patterns facing eachother and bonding the semiconductor chip and the board by applyingpressure/heat, in which

the adhesive for connecting circuit members contains

a resin composition comprising a thermoplastic resin, a crosslinkableresin and a hardening agent for forming a crosslink structure of thecrosslinkable resin; and

composite oxide particles dispersed in the resin composition.

(2) The adhesive for connecting circuit members according to item (1),in which the refractive index difference between the resin compositionand the composite oxide particles falls within ±0.06.

(3) The adhesive for connecting circuit members according to item (1) or(2), in which the composite oxide particles have a refractive index of1.5 to 1.7 and are particles formed of a composite oxide comprising twoor more types of metal elements.

(4) The adhesive for connecting circuit members according to any ofitems (1) to (3), in which the composite oxide particles are particlesformed of at least one type of metal element selected from aluminum andmagnesium, and an oxide comprising a metal element except the abovemetal elements or a metalloid element.

(5) The adhesive for connecting circuit members according to item (4),in which the metalloid element is silicon and/or boron.

(6) The adhesive for connecting circuit members according to any ofitems (1) to (5), in which the composite oxide particles are particlescomprising a composite oxide having a specific gravity of 4 or less.

(7) An adhesive for connecting circuit members, which is interposedbetween a semiconductor chip having protruding connecting terminals anda board having wiring patterns formed thereon for electricallyconnecting the connecting terminals and the wiring patterns facing eachother and bonding the semiconductor chip and the board by applyingpressure/heat, in which

the adhesive for connecting circuit members contains

a resin composition containing a thermoplastic resin, a crosslinkableresin and a hardening agent for forming a crosslink structure of thecrosslinkable resin; and

composite oxide particles comprising cordierite particles dispersed inthe resin composition.

(8) The adhesive for connecting circuit members according to any ofitems (1) to (7), in which the composite oxide particles are compositeoxide particles having an average particle size of 3 μm or less.

(9) The adhesive for connecting circuit members according to any ofitems (1) to (8), in which the composite oxide particles are comprisedin an amount of 25 to 200 parts by weight relative to 100 parts byweight of the resin composition.

(10) The adhesive for connecting circuit members according to any ofitems (1) to (9), in which the adhesive for connecting circuit membersin an unhardened state has a visible-light parallel transmittance of 15to 100%.

(11) The adhesive for connecting circuit members according to any ofitems (1) to (10), in which a reactivity of the adhesive for connectingcircuit members measured by a differential scanning calorimeter (DSC)after heating at 180° C. for 20 seconds is 80% or more.

(12) The adhesive for connecting circuit members according to any ofitems (1) to (11), in which a linear expansion coefficient of theadhesive for connecting circuit members measured at 40° C. to 100° C.after hardening is 70×10⁻⁶/° C. or less.

(13) The adhesive for connecting circuit members according to any ofitems (1) to (12), in which the thermoplastic resin is a copolymerizableresin having a weight average molecular weight of 1 million or less anda glass transition temperature (Tg) of 40° C. or less, and having areactive functional group with the crosslinkable resin in a side chain,

the crosslinkable resin is an epoxy resin, and

the hardening agent is a microencapsulated hardening agent.

(14) The adhesive for connecting circuit members according to any ofitems (1) to (13), comprising conductive particles having an averageparticle size of 3 to 5 μm dispersed therein.

(15) A semiconductor device comprising an electronic component in whicha semiconductor chip having connecting terminals and a board havingwiring patterns formed thereon are electrically connected by theadhesive for connecting circuit members according to any of items (1) to(14).

Effect of the Invention

The present invention provides a circuit-member connecting adhesive,which has excellent adhesiveness to a wafer in an unhardened state,through which an alignment mark provided to the wafer is highlyrecognizable, and has excellent adhesiveness and connection reliabilitybetween a chip and a board in a hardened state, and provides asemiconductor device using the same. More specifically, there isprovided a circuit-member connecting adhesive optimized for satisfyingthe following properties: compatibility between peel-off suppressionduring dicing and simple release after dicing by optimizing theadhesiveness to a wafer and the adhesiveness to a dicing tape; highelasticity of a film in an unhardened state in order to perform dicingwhile suppressing occurrence of fibrous burr and crack, etc.; visibilityof an alignment mark through a resin, which enables accurate alignmentof a diced adhesive chip with a circuit board; a high reactivity, whichenables hardening at low temperature for short time in a chip mountingprocess; and a high connection reliability attained by lowering thermalexpansion by a large content of filler. In addition, there is providedan anisotropic conductive adhesive wherein conductive particles aredispersed in the circuit-member connecting adhesive and a semiconductordevice using these adhesives.

According to the circuit-member connecting adhesive of the presentinvention, a semiconductor chip attached with an adhesive can beobtained by a preset underfill method, which can deal with narrow-pitchand narrow-gap tendency, without contamination during a dicing processand without difficulty in peeling-off from a dicing tape after thedicing process. In addition, not only transparency, which enablesaccurate alignment of an adhesive chip but also high connectionreliability obtained by lowering a thermal expansion coefficient can beobtained at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a circuit-member connecting adhesiveaccording to a first embodiment;

FIG. 2 is a sectional view of a circuit-member connecting adhesiveaccording to a second embodiment;

FIG. 3 is a sectional view of a semiconductor chip having protrudingconnecting terminals;

FIG. 4 is a sectional view of a board having wiring patterns formedthereon;

FIG. 5 is a sectional view of an electronic component in which asemiconductor chip and a board are electrically connected and bonded bya circuit-member connecting adhesive according to the first embodiment;

FIG. 6 is a sectional view of an electronic component in which asemiconductor chip and a board are electrically connected and bonded bya circuit-member connecting adhesive according to the second embodiment;

FIG. 7 is a sectional view of an electronic component in which asemiconductor chip and a board are electrically connected and bonded bya circuit-member connecting adhesive according to the second embodiment;

FIG. 8 is a sectional view illustrating an embodiment of a manufacturingstep of the electronic component shown in FIG. 5. FIG. 8 (a) is asectional view of a laminate formed by laminating a circuit-memberconnecting adhesive according to the first embodiment on a semiconductorchip; and FIG. 8 (b) is a sectional view of the board;

FIG. 9 is a sectional view illustrating an embodiment of a manufacturingstep of the electronic component shown in FIG. 6 or 7. FIG. 9 (a) is asectional view of a laminate formed by laminating a circuit-memberconnecting adhesive according to the second embodiment on asemiconductor chip and FIG. 9 (b) is a sectional view of the board;

FIG. 10 is a sectional view of a semiconductor device having anelectronic component in which a semiconductor chip and a board areelectrically connected by a circuit-member connecting adhesive accordingto the first embodiment; and

FIG. 11 is a view showing transmissivity of adhesives for connectingcircuit members.

DESCRIPTION OF SYMBOLS

1 Circuit-member connecting adhesive according to the first embodiment;2 Circuit-member connecting adhesive according to the second embodiment;3 Semiconductor chip; 4 Board; 5 Electronic component mounting board; 10Adhesive; 12 Conductive particles; 20 Semiconductor component; 22, 42Connecting terminal; 30, 40 Insulating board; 32 Wiring pattern; 34Solder ball

BEST MODES FOR CARRYING OUT THE INVENTION

Referring to the accompanying drawings, preferred embodiments will bedescribed below. Note that identical symbols are used to designate thesame structural elements in the description of the drawings andduplication of description is avoided. Furthermore, the figures arepartly exaggerated in order to facilitate understanding and thus thedimensional ratios do not always coincide with those used in thedescription.

FIG. 1 is a sectional view of a circuit-member connecting adhesiveaccording to a first embodiment and FIG. 2 is a sectional view of acircuit-member connecting adhesive according to a second embodiment.

The circuit-member connecting adhesive 1 according to the firstembodiment shown in FIG. 1 is a film adhesive constituted of an adhesive10, which is formed of a resin composition comprising a thermoplasticresin, a crosslinkable resin and a hardening agent and composite oxideparticles dispersed in the resin composition.

The circuit-member connecting adhesive 2 according to the secondembodiment shown in FIG. 2 is a film adhesive constituted of theadhesive 10, which is formed of a resin composition comprising athermoplastic resin, a crosslinkable resin and a hardening agent andcomposite oxide particles dispersed in the resin composition, andconductive particles 12 dispersed in the adhesive 10, which are 3 to 5μm in average particle size.

FIG. 3 is a sectional view of a semiconductor chip having protrudingconnecting terminals and to be joined by a circuit-member connectingadhesive of the present invention. The semiconductor chip 3 shown inFIG. 3 has a semiconductor component 20 and connecting terminals 22formed so as to protrude on the main surface.

FIG. 4 is a sectional view of a board having wiring patterns formedthereon and to be joined by a circuit-member connecting adhesive of thepresent invention. The board 4 shown in FIG. 4 has an insulating board30 and wiring patterns (electrode) 32 formed on the main surface.

FIG. 5 is a sectional view of an electronic component in which asemiconductor chip and a board are electrically connected and bonded bya circuit-member connecting adhesive according to the first embodiment.In the electronic component shown in FIG. 5, a semiconductor chip 3,which has a semiconductor component 20 and connecting terminals 22, andthe board 4, which has the insulating board 30 and the wiring patterns32, are arranged such that the connecting terminals 22 and the wiringpatterns 32 face each other. The semiconductor chip 3 and the board 4are bonded by the circuit-member connecting adhesive 1 according to thefirst embodiment comprising the adhesive 10; at the same time, theconnecting terminals 22 and the wiring patterns 32 are brought intocontact with each other and electrically connected.

FIG. 6 is a sectional view of an electronic component in which asemiconductor chip and a board are electrically connected and bonded bya circuit-member connecting adhesive according to the second embodiment.In the electronic component shown in FIG. 6, a semiconductor chip 3,which has a semiconductor component 20 and a connecting terminal 22, anda board 4, which has an insulating board 30 and wiring patterns 32, arearranged such that the connecting terminals 22 and the wiring patterns32 face each other. The semiconductor chip 3 and the board 4 are bondedby the circuit-member connecting adhesive 2 according to the secondembodiment formed of the adhesive 10 and the conductive particles 12; atthe same time, the connecting terminals 22 and the wiring patterns 32are brought into contact with each other and electrically connected.Note that the conductive particles 12 are present at positions causingno short circuit between the connecting terminals 22 or between thewiring patterns 32.

FIG. 7 is a sectional view of an electronic component in which asemiconductor chip and a board are electrically connected and bonded bya circuit-member connecting adhesive according to the second embodiment,and shows a different embodiment of the electronic component shown inFIG. 6. In the electronic component shown in FIG. 7, the semiconductorchip 3, which has a semiconductor component 20 and connecting terminals22, and the board 4, which has an insulating board 30 and wiringpatterns 32 are arranged such that the connecting terminals 22 and thewiring patterns 32 face each other. The semiconductor chip 3 and theboard 4 are bonded by a circuit-member connecting adhesive according tothe second embodiment comprising the adhesive 10 and the conductiveparticles 12; at the same time, the connecting terminals 22 and thewiring patterns 32 are brought into contact with each other withconductive particles 12 interposed between them, and electricallyconnected. Note that the conductive particles 12, which are not involvedin electrical connection, are present at positions causing no shortcircuit between the connecting terminals 22 or the wiring patterns 32.

FIG. 8 is a sectional view illustrating an embodiment of a manufacturingstep of the electronic component shown in FIG. 5. FIG. 8 (a) is asectional view of a laminate formed by laminating a circuit-memberconnecting adhesive according to the first embodiment comprising theadhesive 10 on a semiconductor chip 3, which has the semiconductorcomponent 20 and the connecting terminals 22, on the side having theconnecting terminals 22. FIG. 8( b) is a sectional view of the board 4having the insulating board 30 and the wiring patterns 32. As shown inFIG. 8, the laminate of FIG. 8( a) and the board of FIG. 8( b) aresubjected to pressure-bonding such that the connecting terminals 22 andthe wiring patterns 32 face each other and the circuit-member connectingadhesive 1 is heated under pressure to obtain the electronic componentshown in FIG. 5.

FIG. 9 is a sectional view illustrating an embodiment of a manufacturingstep of the electronic component shown in FIG. 6 or 7. FIG. 9 (a) is asectional view of a laminate formed by laminating a circuit-memberconnecting adhesive 2 according to the second embodiment on asemiconductor chip, which comprising the adhesive 10 and the conductiveparticles 12, on a semiconductor chip 3, which has the semiconductorcomponent 20 and the connecting terminals 22, on the side having theconnecting terminals 22. FIG. 9 (b) is a sectional view of the board 4having the insulating board 30 and the wiring patterns 32. As shown inFIG. 9, the laminate of FIG. 9 (a) and the board of FIG. 9 (b) aresubjected to pressure-bonding such that the connecting terminals 22 andthe wiring patterns 32 face each other and the circuit-member connectingadhesive 2 is heated under pressure to obtain the electronic componentshown in FIG. 6 or 7.

FIG. 10 is a sectional view of a semiconductor device having anelectronic component in which a semiconductor chip is electricallyconnected to a board by a circuit-member connecting adhesive accordingto the first embodiment. The semiconductor device shown in FIG. 10 iscomposed of an electronic component and an electric component mountingboard for mounting the electronic component. In the electronic componentconstituting the semiconductor device of FIG. 10, the semiconductor chip3, which has the semiconductor component 20 and the connecting terminals22, and the board 4, which has the wiring patterns 32 on one of thesurfaces of the insulating board 30 and solder balls 34 on the othersurface, are arranged such that the connecting terminals 22 and thewiring patterns 32 face each other. The semiconductor chip 3 and theboard 4 are bonded by the circuit-member connecting adhesive 1 accordingto the first embodiment composed of the adhesive 10; at the same time,the connecting terminals 22 and the wiring patterns 32 are brought intocontact with each other and electrically connected. Note that the wiringpatterns 32 and the solder balls 34 are allowed to communicate by viaholes (not shown) formed within the insulating board 30. In short, thesemiconductor device shown in FIG. 10 is formed by electricallyconnecting the aforementioned electronic component and the electroniccomponent mounting board 5, in which the connecting terminals 42 areformed on an insulating board 40, such that solder balls 34 arepositioned on the connecting terminals 42 of the electronic componentmounting board 5.

In the present invention, the connecting terminal 22 to be used in thesemiconductor chip 3 is a gold stud bump formed of gold wire, a metalball fixed to the electrode of the semiconductor chip bythermocompression bonding or by using a thermocompression bondingmachine in combination with ultrasonic wave and a metal ball formed byplating or deposition.

The protruding connecting terminal 22 is not always formed of a singlemetal and may contain a plurality of metal components such as gold,silver, copper, nickel, indium, palladium, tin and bismuth, or may be alaminate of layers formed of these metals. The semiconductor chip 3having the protruding connecting terminals 22 may be a semiconductorwafer having the protruding connecting terminals.

To arrange the protruding connecting terminals 22 of the semiconductorchip 3 and the board 4 having the wiring patterns 32 formed thereon soas to face each other, the semiconductor chip 3 preferably has analignment mark in the same surface as that on which the protrudingconnecting terminals are formed. The circuit board to be used as thecircuit board 4 having wiring patterns 32 formed thereon may be anordinary circuit board or a semiconductor chip.

In the case of a circuit board, the wiring patterns 32 can be formed onan insulating board 30, which is formed by impregnating glass cloth ornonwoven cloth with an epoxy resin and a resin having a benzotriazineskeleton, and formed on a board having a build-up layer. The wiringpatterns 32 can be also formed by forming a metal layer such as copperon the surface of an insulating board 30 formed of, e.g., polyimide,glass or ceramics and etching away an unnecessary portion of the metallayer. Alternatively, the wiring patterns can be formed by plating ordepositing a metal on the surface of the insulating board 30.

The wiring patterns 32 are not always formed of a single metal and maycontain a plurality of metal components such as gold, silver, copper,nickel, indium, palladium, tin and bismuth, or may be a laminate oflayers of these metals. Furthermore, in the case where the board is asemiconductor chip, in which the wiring patterns 32 are usually formedof aluminum, a metal layer of gold, silver, copper, nickel, indium,palladium, tin and bismuth may be formed on the surface.

The state of a semiconductor chip where a circuit-member connectingadhesive is bonded on the surface having protruding connecting terminalscan be obtained by forming a laminate by stacking a semiconductor wafer(before processed into chips) having protruding connecting terminals,the circuit-member connecting adhesive provided on the surface of thesemiconductor wafer having protruding connecting terminals, and a dicingtape whose sticky layer is allowed to face the circuit-member connectingadhesive, sequentially in this order; and cutting the laminate intopieces by dicing; and removing the discrete semiconductor chips attachedwith the circuit-member connecting adhesive from the dicing tape.Alternatively, the state of a semiconductor chip where a circuit-memberconnecting adhesive is bonded on the surface having protrudingconnecting terminals can be also obtained by forming a laminate byproviding a circuit-member connecting adhesive on the connectingterminal surface of a semiconductor wafer (before processed into chips)having protruding connecting terminals and providing a dicing tape suchthat a sticky layer thereof faces the surface of the semiconductor waferhaving no circuit-member connecting adhesive; and cutting the laminateinto pieces by dicing; and removing the discrete semiconductor chipsattached with the circuit-member connecting adhesive from the dicingtape.

As the dicing tape having a sticky material applied to a base tape, acommercially available dicing tape can be used. As a radiationresponsive dicing tape, whose stickiness decreases with UV irradiationsince the sticky layer gradually hardened, thereby facilitating peel-offof a material laminated on the sticky surface, a commercially availableone can be used.

The circuit-member connecting adhesive preferably has the feature thatan alignment mark formed on the circuit surface of the chip can berecognized through the circuit-member connecting adhesive, which isbonded on the surface of a semiconductor chip having the protrudingconnecting terminals. The alignment mark can be recognized by achip-recognition unit integrated in an ordinary flip-chip bonder.

The recognition unit is generally constituted of a halogen light sourcehaving a halogen lamp, a light guide, an irradiation apparatus and a CCDcamera. The image is taken by the CCD camera, compared to the imagepattern for use in alignment, which has been previously stored in theimage processing unit, and determined whether both are consistent witheach other. In this way, an alignment operation is performed.

The expression “an alignment mark can be recognized” herein means thatthe image of an alignment mark taken by the chip-recognition unit of theflip-chip bonder has good consistency with the image of the alignmentmark stored therein and thus an alignment operation can be performed.

For example, when flip-chip bonder-CB-1050 (trade name, manufactured byAthlete FA Corporation) is used, a laminate, which has a circuit-memberconnecting adhesive bonded on the surface having protruding connectingterminals, is adsorbed by an adsorption nozzle of the flip-chip bonderat the opposite surface (having the protruding connecting terminals),and thereafter, a recognition mark formed on the semiconductor chipsurface is photographed through the adhesive layer by a recognition unitintegrated in the apparatus. In the case where the recognition markphotographed is consistent with the recognition mark of thesemiconductor chip previously taken in the image processing apparatus,determining that alignment can be performed, the adhesive is treated asa recognizable circuit-member connecting adhesive. In contrast, in thecase of determining that alignment cannot be performed, the adhesive istreated as a non-recognizable circuit-member connecting adhesive. Inthis manner, the adhesives can be selected.

The circuit-member connecting adhesive in a non-hardened statepreferably has a parallel transmittance of 15 to 100%, more preferably18 to 100% and further preferably 25 to 100%. When the paralleltransmittance is less than 15%, a recognition mark cannot be recognizedby the flip-chip bonder, with the result that alignment operation maynot be performed.

The parallel transmittance can be measured by a turbidimeter NDH2000(trade name, manufactured by Nippon Denshoku Industries Co., Ltd) basedon integrating-sphere photoelectric photometry. To explain morespecifically, a 50 μm-thick PET film manufactured by Teijin Dupont Films(Purex, transmittance of whole light beams: 90.45, haze: 4.47) is usedas a reference substance. After correction is made, a circuit-memberconnecting adhesive is applied to a PET base to a thickness of 25 μm andsubjected to measurement. From the measurement results, turbidity, wholelight beam transmittance, diffusion transmittance and paralleltransmittance can be obtained.

The visible-light transmittance can be measured by a U-3310 typespectrophotometer (trade name, manufactured by Hitachi Ltd.). To explainmore specifically, a 50 μm-thick PET film manufactured by Teijin DupontFilms (Purex, 555 nm, transmittance: 86.03%) is used as a referencesubstance. After baseline correction measurement is made, acircuit-member connecting adhesive is applied to a PET base to athickness of 25 μm. Then, a transmittance of visible light within therange of 400 nm to 800 nm can be measured. Since the relative intensityof a halogen light source used in the flip-chip bonder to that of thelight guide is the strongest in the range of a wavelength of 550 nm to600 nm, transmittance can be compared based on the transmittance at 555nm in the present invention.

The circuit-member connecting adhesive preferably has a reactivity(measured by DSC after heated at 180° C. for 20 seconds) is preferablyof 80% or more, more preferably 84% or more, and further preferably 86%or more. Note that the reactivity can be measured, for example, by thefollowing method. First, 2 to 10 mg of the circuit-member connectingadhesive before a reaction is weighed in an aluminum measurementcontainer. Calorific value of the adhesive is measured by DSC whileraising a temperature at a rate of 20° C./min from 30 to 300° C. toobtain an initial calorific value. Then, the circuit-member connectingadhesive is heated at 180° C. for 20 seconds by use of a heating head ofa thermocompression bonding apparatus to obtain a heated circuit-memberconnecting adhesive. Then, 2 to 10 mg of the heated circuit-memberconnecting adhesive is taken and colorific value is measured by DSC inthe same conditions as above to obtain a calorific value after heating.Based on the calorific values thus obtained, a reactivity (%) iscalculated in accordance with the following formula:

(Initial calorific value−calorific value after heating)/(initialcalorific value)×100.

The circuit-member connecting adhesive preferably has an adhesive forceof 10 N/m or less to a UV-irradiated dicing tape and an adhesive forceof 70 N/m or more to a semiconductor wafer. When the adhesive force to adicing tape after UV irradiation exceeds 10 N/m, the semiconductor chipsmay break and the adhesive layer may deform in a process where diced andseparated semiconductor chips attached with the circuit-memberconnecting adhesive are peeled off from the dicing tape. On the otherhand, when the adhesive force to a semiconductor wafer is less than 70N/m, chips and the adhesive may separate at the interface by the effectof shock and hydraulic pressure given by rotary cleavage of a blade in adicing process.

The adhesive force between the circuit-member connecting adhesive andthe UV irradiated dicing tape can be measured, for example, by thefollowing method. First, the circuit-member connecting adhesive islaminated on a wafer by a laminator set at a heating temperature of 80°C. The dicing tape before UV irradiation is laminated at 40° C. suchthat the sticky surface of the tape is brought into contact with thecircuit-member connecting adhesive. Thereafter, UV rays (about 300 mJ at15 mW) are applied to the dicing tape. Subsequently, slits are made inthe UV irradiated dicing tape at width of 10 mm to prepare strips fortensile strength measurement.

Subsequently, the wafer is clamped on a stage and one end of thedicing-tape strip is fixed to a pulling jig of a tensile forcemeasurement machine. The UV irradiated dicing tape and thecircuit-member connecting adhesive are peeled off. In this manner, a 90°peel test is performed. Based on the measurement, the adhesive forcebetween the UV irradiated dicing tape and the circuit-member connectingadhesive can be measured.

The adhesive force between the circuit-member connecting adhesive andthe semiconductor wafer can be measured, for example, by the followingmethod. First, the circuit-member connecting adhesive is laminated onthe wafer by a laminator set at a heating temperature of 80° C.Thereafter, Kapton (registered trade mark) tape (manufactured by NittoDenko Corporation, 10 mm in width, 25 μm in thickness) is bonded to thecircuit-member connecting adhesive so as to face the sticky surfacethereof and made tight sufficiently. After that, slits are made in thecircuit-member connecting adhesive bonded to Kapton (registered trademark) tape at width of 10 mm.

One end of the resultant laminate of the circuit-member connectingadhesive and Kapton (registered trade mark) tape is peeled off from thewafer and fixed to a pulling jig of a tensile force measurement machine.The wafer is clamped on a stage and one end of a strip is pulled up topeel off the circuit-member connecting adhesive from the wafer. In thismanner, a 90° peel test is performed. Based on the measurement, theadhesive force between the circuit-member connecting adhesive and thewafer can be measured.

After bonding, the circuit-member connecting adhesive, in order tosuppress temperature change and expansion due to heating and moistureadsorption, etc., after connecting between the semiconductor chip and acircuit board, preferably has a linear expansion coefficient (afterhardening, measured at 40° C. to 100° C.) of 70×10⁻⁶/° C. or less, morepreferably 60×10⁻⁶/° C. or less, further preferably 55×10⁻⁶/° C. orless, and particularly preferably 50×10⁻⁶/° C. or less. When the linearexpansion coefficient (after hardening) exceeds 70×10⁻⁶/° C., theelectric contact between connecting terminals of a semiconductor chipand wiring of a circuit board may not be maintained due to temperaturechange and expansion by heating and moisture adsorption after mounting.

The circuit-member connecting adhesive contains an adhesive resincomposition and composite oxide particles. The adhesive resincomposition preferably has a parallel transmittance of 15% or more, morepreferably 30% or more, and further preferably 40% or more. The casewhere the parallel transmittance is 40% or more is preferred since apredetermined transmittance can be satisfactorily obtained even if thecontent of composite oxide particles is high. When the paralleltransmittance of the adhesive resin composition is less than 15% orless, a recognition mark cannot be recognized by a flip-chip bonder evenif composite oxide particles are not added. As a result, an alignmentoperation may not be performed.

The composite oxide particles to be used in the present inventionpreferably have a refractive index of 1.5 to 1.7 and more preferably1.53 to 1.65. If the refractive index of the composite oxide particlesis less than 1.5, when the particles are blended in the adhesive resincomposition, the refractive index difference from the resin compositionbecomes large. As a result, light is scattered when it passes throughthe circuit-member connecting adhesive and alignment may not beperformed. On the other hand, if the refractive index exceeds 1.7, therefractive index difference from the resin increases, with the resultthat light is scattered and alignment may not be performed. Therefractive index can be measured by Abbe refractometer using sodiumD-line (589 nm) as a light source.

The composite oxide particles to be used in the present inventionpreferably have an average particle size of 15 μm or less and a maximumparticle size of 40 μm or less, more preferably have an average particlesize of 5 μm or less, and further preferably have an average particlesize of 3 μm or less. The composite oxide particles are particles havingan average particle size of 3 μm or less and a maximum particle size of20 μm or less, and furthermore, particles particularly preferably havingan average particle size of 3 μm or less and a maximum particle size of5 μm or less. The case where the average particle size exceeds 15 μm isnot preferred. This is because composite oxide particles enter betweenbumps (connecting terminals) of a chip and electrodes of a circuit board(a board having wiring patterns formed thereon). In particular, whenmounting is performed under low pressure and when bumps are made of ahard substance such as nickel, embedding is not performed and electriccontact is suppressed. In contrast, when the maximum particle sizeexceeds 40 μm, the particle size may exceed the gap between the chip andthe board. Consequently, the particles may damage the circuit of thechip or the circuit of the board when pressure is applied during amounting process.

The composite oxide particles to be used in the present inventionpreferably have a specific gravity of 4 or less, more preferably 2 to 4,and further preferably 2 to 3.2. If the specific gravity exceeds 4, whenthe particles are added to a varnish of an adhesive resin composition,they may precipitate in the vanish due to a large difference of specificgravity. As a result, the circuit-member connecting adhesive havingcomposite oxide particles uniformly dispersed therein may not beobtained.

Furthermore, the composite oxide particles to be used in the presentinvention preferably have a refractive-index difference with theadhesive resin composition within ±0.06, more preferably within ±0.02,and further preferably within ±0.01. When the refractive-indexdifference exceeds ±0.06, the transmittance of the adhesive resincomposition decreases by adding the particles. As a result, an alignmentmark formed on the circuit surface of a chip cannot be recognized insome cases through the circuit-member connecting adhesive bonded on thesurface of a semiconductor chip having the protruding connectingterminals thereon.

As such a composite oxide, one having a refractive index of 1.5 to 1.7and a refractive-index difference with an adhesive resin compositionwithin ±0.06 is particularly preferred. Examples of such a compositeoxide include oxides containing metal elements such as zinc, aluminum,antimony, ytterbium, yttrium, indium, erbium, osmium, cadmium, calcium,potassium, silver, chrome, cobalt, samarium, dysprosium, zirconium, tin,cerium, tungsten, strontium, tantalum, titanium, iron, copper, sodium,niobium, nickel, vanadium, hafnium, palladium, barium, bismuth,praseodymium, beryllium, magnesium, manganese, molybdenum, europium,lanthanum, phosphorus, lutetium, ruthenium, rhodium and boron. They maybe used in combination.

The composite oxide is preferably a compound containing not less thantwo types of metals as a raw material which has a different structurefrom an oxide structure formed of each of the raw material metals.Particularly preferably, the composite oxide particles are formed of atleast one type of metal element selected from aluminum, magnesium ortitanium and an oxide compound containing at least two types of elementsexcept the aforementioned elements. As such a composite oxide, aluminumborate, cordierite, forsterite and mullite, etc may be mentioned. Thecomposite oxide may be an aluminum composite oxide or a siliconecomposite oxide substituted with a metal element such as magnesium. Notethat, in the present invention, a metalloid element (half-metal) such assilicon and boron is treated as a metal for forming a composite oxide.

The linear expansion coefficient of the composite oxide particles ispreferably 7×10⁻⁶/° C. in the temperature range of 0 to 700° C. or less,and more preferably 3×10⁻⁶/° C. or less. When the linear expansioncoefficient exceeds 7×10⁻⁶/° C., a large amount of composite oxideparticles must be added in order to reduce the linear expansioncoefficient of the circuit-member connecting adhesive.

As the composite oxide particles, cordierite is further preferable sincefine adjustment of the refractive index can be made and the linearexpansion coefficient is low. Cordierite is a compound represented by ageneral composition of MgO/Al₂O₃/SiO₂ and has a refractive index of1.54. The ratio of MgO/Al₂O₃/SiO₂ is 2/2/5. Fine adjustment of therefractive index can be made by slightly changing the ratio. The linearexpansion coefficient of a crystallized compound is 2×10⁻⁶/° C. or less.The composite oxide particles contained in the circuit-member connectingadhesive preferably contain cordierite particles. The composite oxideparticles may contain cordierite particles alone or may containcomposite oxide particles other than cordierite particles. In the lattercase, the content of the cordierite particles is preferably 50 wt % ormore based on the total amount of the composite oxide particles, morepreferably 70 wt % or more, and further preferably 90 wt % or more.

In the circuit-member connecting adhesive, the content of the compositeoxide particles is preferably 25 to 200 parts by weight relative to 100parts by weight of a resin composition. The content is more preferably25 to 150 parts by weight, further preferably 50 to 150 parts by weight,and particularly preferably 75 to 125 parts by weight. When the contentof the composite oxide particles is less than 25 parts by weight, thelinear expansion coefficient of the circuit-member connecting adhesivemay increase and the elastic modulus may decrease. In such a case,connection reliability between a semiconductor chip and a board afterpressure-bonding decreases. On the other hand, when the content of thecomposite oxide particles exceeds 200 parts by weight, the meltviscosity of the circuit-member connecting adhesive increases, with theresult that sufficient contact between protruding electrodes of asemiconductor to the circuit of a board may become difficult.

The circuit-member connecting adhesive contains a resin composition andcomposite oxide particles dispersed in the resin composition. The resincomposition contains a thermoplastic resin, a crosslinkable resin and ahardening agent capable of forming a crosslink structure of this resin.The resin composition or circuit-member connecting adhesive may containother additives (a filler, a plasticizer, a coloring agent, acrosslinking auxiliary, etc.) as long as the effect of the presentinvention is not inhibited. Note that the resin composition may consistonly of a thermoplastic resin, a crosslinkable resin and a hardeningagent capable of forming a crosslink structure of this resin. Thecircuit-member connecting adhesive may consist only of the resincomposition and composite oxide particles dispersed in the resincomposition.

As the thermoplastic resin contained in the resin composition, mentionmay be made of a polyolefin (such as polyethylene, polypropylene), anethylene copolymer (such as an ethylene-α olefin copolymer, anethylene-vinyl acetate copolymer, an ethylene-(meth)acrylate copolymer),a styrene block copolymer, an acrylic polymer (which refers to a polymerof monomers having a (meth)acryloyl group), an acrylic copolymer (whichrefers to a copolymer containing a monomer having a (meth)acryloyl groupas a co-monomer) and a phenoxy resin. An acrylic polymer and acryliccopolymer or a phenoxy resin is preferred. The thermoplastic resinpreferably has a weight average molecular weight of 1 million or less,more preferably 0.5 millions or less, and further preferably 0.3millions or less. Furthermore, the Tg of the thermoplastic resin ispreferably 40° C. or less, and more preferably 35° C. or less.

The crosslinkable resin contained in the resin composition is a resin(three-dimensional crosslinking resin) forming a three dimensionalcrosslink by the action of the hardening agent used in combination withenergy application such as heat/light irradiation, and preferably aresin having a functional group reactive to the hardening agent withapplication of heat and light. As such a crosslinkable resin, mentionmay be made of an epoxy resin, a bismaleimide resin, a triazine resin, apolyimide resin, a polyamide resin, a cyanoacrylate resin, a phenolicresin, an unsaturated polyester resin, a melamine resin, a urea resin, apolyurethane resin, a polyisocyanate resin, a furan resin, a resorcinolresin, a xylene resin, a benzoguanamine resin, a diallyl phthalateresin, a silicone resin, a polyvinylbutyral resin, a siloxane-modifiedepoxy resin, a siloxane-modified polyamide-imide resin and an acrylateresin, etc. They may be used singly or as a mixture of two types ormore.

The hardening agent which acts on such a crosslinkable resin to form acrosslinking structure can be determined in accordance with thereactivity (e.g., type of a functional group) of the crosslinkableresin. As the hardening agent, mention may be made of hardening agentsof a phenolic base, imidazole base, hydrazide base, thiol base,benzoxazine, a boron trifluoride-amine complex, a sulfonium salt,amine-imide, a polyamine salt, dicyandiamide and an organic peroxidebase. These hardening agents may be microcapsules having a coat of apolymer substance such as a polyurethane polymer and a polyester polymerto extend its work life.

The thermoplastic resin is preferably a co-polymerizable resin having aweight average molecular weight of 1 million or less (preferably 0.5millions or less, and further preferably 0.3 millions or less) and a Tgof 40° C. or less (preferably 35° C. or less) and containing at leastone functional group reactive to a crosslinkable resin in a side chain.As a hardening agent, a microencapsulated hardening agent is preferred.It is particularly preferred that such a copolymerizable resin may beused in combination with the microencapsulated hardening agent. Notethat Tg (glass transition temperature) can be measured by the DSC methodspecified by JIS K7121 “plastic transition temperature measurementmethod”.

As the copolymerizable resin having a weight average molecular weight of1 million or less and a Tg of 40° C. or less and containing at least onefunctional group reactive to a crosslinkable resin in a side chain, itis preferred to use acrylic copolymers containing an epoxy group, acarboxyl group and a hydroxyl group in a side chain as the functionalgroup reactive to a crosslinkable resin. Particularly, an epoxygroup-containing acrylic copolymer is preferred, which is obtained byusing e.g., glycidyl acrylate or glycidyl methacrylate as a raw materialfor an acrylic copolymer.

As a raw material for use in copolymerization of the copolymerizableresin, use may be made of hydroxy alkyl (meth)acrylates such ashydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate andhydroxybutyl (meth)acrylate; (meth)acrylic esters such as methylmethacrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate,cyclohexyl (meth)acrylate, furfuryl (meth)acrylate, lauryl(meth)acrylate, stearyl (meth)acrylate, trimethylcyclohexyl(meth)acrylate, tricyclodecyl (meth)acrylate, andtetracyclododecyl-3-acrylate; styrene, vinyl toluene, polypropyleneglycol monomethacrylate, hydroxyethyl acrylate, acrylonitrile, benzylmethacrylate, cyclohexylmaleimide and the like.

The microencapsulated hardening agent is referred to one containing ahardening agent serving as a core, which is substantially coated with afilm such as a thin film made of a polymer substance such aspolyurethane, polystyrene, gelatin or polyisocyanate; an inorganicsubstance such as calcium silicate or zeolite; and a metal such asnickel or copper. The average particle size of the microencapsulatedhardening agent is preferably 10 μm or less, and more preferably 5 μm orless.

The resin composition may contain a microencapsulated hardening agent ora non-microencapsulated hardening agent. The resin composition may alsocontain a coupling agent in order to increase adhesion intensity and athermoplastic resin such as polyester, polyurethane, polyvinyl butyral,a polyarylate, polymethyl methacrylate, acrylic rubber, polystyrene,phenoxy resin, NBR, SBR, polyimide and a silicone-modified resin(acrylic silicone, epoxy silicone, polyimide silicone) to contribute tofilm formability. Furthermore, to modify the surface of composite oxideparticles, silicone oil, polysiloxane, a silicone oligomer and acoupling agent may be contained.

The circuit-member connecting adhesive can be an anisotropic conductiveadhesive which is prepared by adding conductive particles having aparticle size of 3 to 5 μm and coated with an organic polymer compoundand/or metal conductive particles. As the conductive particles beforecoated with an organic polymer compound, metal particles of Au, Ag, Ni,Cu and solder and carbon particles may be used. To obtain a sufficientpot life, the surface of the particles may not be made of a transitionmetal such as Ni or Cu and preferably made of a precious metal such asAu, Ag or platinum, and more preferably Au.

Furthermore, the surface of a transition metal such as Ni may be coatedwith a precious metal such as Au. Moreover, particles, which are formedby coating a non-conductive glass, ceramic and plastic, etc. with aconductive layer as mentioned above and adding a precious metal as theoutermost layer, and thermofusion metal particles are preferred. This isbecause they deform when heat or pressure is applied and cancel outvariation in height of electrodes to increase the contact area with theelectrodes when connected, thereby improving reliability. The thicknessof the precious-metal coating layer is preferably 100 angstroms or morein order to obtain good resistance.

However, when a precious-metal layer is formed on a transition metalsuch as Ni, if there is a defect of the precious metal layer; i.e., adefect of the precious metal layer produced in mixing and dispersingconductive particles, an oxidation-reduction reaction occurs.Consequently, free radicals are generated and decrease storageability.Therefore, the thickness of the precious metal layer is preferred to be300 angstroms or more. As the thickness increases, the aforementionedeffects come to be saturated. For the reason, the thickness is, but notparticularly limited to, desirably at most 1 μm. The surface of theconductive particles is coated with an organic polymer compound asneeded.

The organic polymer compound to be used for coating is preferably watersoluble because coating operation can be easily performed. As the watersoluble polymer, mention may be made of polysaccharides such as alginicacid, pectic acid, carboxymethylcellulose, agar, curdlan and pullulan;polycarboxylic acids such as polyaspartic acid, polyglutaminic acid,polylysine, polymalic acid, polymethacrylic acid, ammoniumpolymethacrylate, sodium polymethacrylate, polyamic acid, polymaleicacid, polyitaconic acid, polyfumaric acid, poly(p-styrene carboxylicacid), polyacrylic acid, polyacrylamide, methyl polyacrylate, ethylpolyacrylate, ammonium polyacrylate, sodium polyacrylate, polyamic acid,ammonium polyamidate, sodium polyamidate and polyglyoxylic acid;polycarboxylic ester and salts thereof; and vinyl monomers such aspolyvinyl alcohol, polyvinyl pyrrolidone and polyacrolein. Thesecompounds may be used singly or in combination of two types or more.

The thickness of the coating is preferably 1 μm or less. Sinceconductive particles are electrically connected with connectingterminals by eliminating the coating. Therefore, the part of the coatingin contact with the connecting terminals must be eliminated in a heatingand pressurizing process. The content of the conductive particles may bevaried depending upon the use within the range of 0.1 to 30 parts byvolume relative to 100 parts by volume of the adhesive resin component.To prevent a problem such as short circuit to an adjacent circuit byexcessive conductive particles, the content of the conductive particlesis more preferably 0.1 to 10 parts by volume.

A laminate, which is formed of a semiconductor wafer having protrudingconnecting terminals, the circuit-member connecting adhesive (orcircuit-member connecting anisotropic conductive adhesive) and a dicingtape that is to be hardened by UV irradiation, can be also obtained bylaminating the semiconductor wafer and the circuit-member connectingadhesive by an apparatus having a heating mechanism and a pressurizingroller or an apparatus having a heating mechanism or a vacuum pressmechanism and thereafter, further laminating with the dicing tape by anapparatus such as a wafer mounter.

Furthermore, the laminate, which is formed of a semiconductor waferhaving protruding connecting terminals, the circuit-member connectingadhesive (or circuit-member connecting anisotropic conductive adhesive)and a dicing tape that is to be hardened by UV irradiation, can be alsoobtained by laminating the circuit-member connecting adhesive and thedicing tape to prepare a laminate, that is then laminated on thesemiconductor wafer by a wafer mounter having a heating mechanism and apressurizing roller or a wafer mounter having a heating mechanism or avacuum press mechanism.

Laminating of a semiconductor wafer and a circuit-member connectingadhesive or laminating a laminate of a semiconductor wafer and acircuit-member connecting adhesive is preferably performed at atemperature at which the circuit-member connecting adhesive is softened,for example, preferably performed while heating to 40 to 80° C., morepreferably while heating to 60 to 80° C., further preferably whileheating to 70 to 80° C.

When laminating is performed at less than a softening temperature of thecircuit-member connecting adhesive, the protruding connecting terminalsof a semiconductor wafer are not sufficiently embedded in the peripheralportion and voids are involved, which may cause peel-off in a dicingprocess, distortion of the circuit-member connecting adhesive during apick-up process, invisibility of a recognition mark during an alignmentprocess. Furthermore, connection reliability may decrease due to thevoids.

When a laminate, which is formed of a semiconductor wafer, acircuit-member connecting adhesive and a dicing tape, are diced, ascribe line can be aligned by use of an IR recognition camera byrecognizing an alignment mark on a circuit pattern of the semiconductorwafer or an alignment mark for dicing through the wafer.

In a laminate, which is formed of a semiconductor wafer, acircuit-member connecting adhesive and a dicing tape, a step of cuttingthe semiconductor wafer and the circuit-member connecting adhesive canbe performed by a dicer usually used. The cutting by the dicer isperformed in accordance with a step generally called as dicing.

Dicing may be preferably performed stepwise. In the first step, a waferalone is cut. In the second step, the wafer remaining in the cut grooveof the first step and the circuit-member connecting adhesive arepreferably cut until the interface with the dicing tape or partly withinthe dicing tape.

A laminate, which is formed of a semiconductor wafer, a circuit-memberconnecting adhesive and a dicing tape, can be diced by a laser. In theUV irradiation step after dicing, UV irradiation (about 150 to 300 mJ)can be applied to the dicing tape by a general light-exposure apparatusor the like at 15 to 30 mW.

The dicing tape and the adhesive are separated by pushing the dicingtape toward the semiconductor wafer to obtain diced (discrete)semiconductor chips attached with an adhesive. This step can be carriedout by an apparatus capable of picking up the chips from the wafer. Thedicing tape is pressed from the opposite surface of the tape on whichsemiconductor chips are mounted so as to extend by pressure. In thisway, the circuit-member connecting adhesive and the UV irradiated dicingtape are peeled off by being separated at the interface thereof.

An adsorption step, an alignment step and a heating/pressurizing step ofadhesive chips can be carried out by a general flip-chip bonder.Alternatively, the adsorption step and the alignment step are carriedout, and the semiconductor chips aligned are provisionally fixed on aboard and the heating/pressurizing step may be performed by apressure-bonding apparatus (exclusively performing pressure-bonding) tomake a connection. Furthermore, connection can be made not only byapplying heat and pressure but also while applying ultrasonic wave.

EXAMPLES

The present invention will be more specifically described below by wayof Examples; however, the present invention is not limited to theseExamples.

Example 1

As a crosslinkable resin, an epoxy resin NC 7000 (trade name,manufactured by Nippon Kayaku Co., Ltd.): 15 parts by weight, was used.As a hardening agent reacting with the crosslinkable resin,phenol-aralkyl resin XLC-LL (trade name, manufactured by MitsuiChemicals Inc.): 15 parts by weight, was used. As a copolymerizableresin having a molecular weight of 1 million or less and a Tg of 40° C.or less and containing at least one functional group reactive to thecrosslinkable resin in a side chain, an epoxy group-containing acrylicrubber HTR-860P-3 (trade name, manufactured by Nagase ChemteXCorporation, the weight average molecular weight: 0.3 million): 20 partsby weight, was used. As microencapsulated hardening agent, HX-3941HP(trade name, manufactured by Asahi Kasei Corporation): 50 parts byweight and a silane coupling agent SH6040 (trade name, manufactured byToray Dow Corning Silicone, Co., Ltd.) were used. The aforementionedsubstances were dissolved in a toluene/ethyl acetate solvent mixture inaccordance with the composition listed in Table 1 to obtain a varnish ofan adhesive resin composition.

Part of the varnish was applied onto a separator film (PET film) by aroll coater, and the dried in an oven of 70° C. for 10 minutes to obtaina 25 μm-thick adhesive resin composition on the separator. The film wasplaced on a sample stage of Abbe refractometer (sodium D line). Afterthe separator was peeled off, a single droplet of matching oil wasdropped and a test piece having a refractive index of 1.74 was placed.Then, a refractive index was measured. As a result, the refractive indexof the adhesive resin composition was 1.59 (25° C.).

On the other hand, to the varnish, cordierite particles of 1 μm inaverage particle size (2MgO.2Al₂O₃.5SiO₂, specific gravity: 2.4, linearexpansion coefficient: 1.5×10⁻⁶/° C., refractive index: 1.54), whichwere weighed, pulverized and subjected to 5 μm-classification to removelarge particles, were mixed in accordance with the composition listed inTable 1 and stirred to disperse. Thereafter, the varnish was appliedonto a separator film (PET film) by use of a roll coater and then driedin an oven of 70° C. for 10 minutes to obtain a 25 μm-thick transparencyconfirmation film on the separator. As shown in FIG. 11, an image on therear side of the obtained transparency confirmation film was recognizedthrough the film.

Aside from the above, to the varnish, cordierite particles of 1 μm inaverage particle size (2MgO.2Al₂O₃.5SiO₂, specific gravity: 2.4, linearexpansion coefficient: 1.5×10⁻⁶/° C., refractive index: 1.54), whichwere weighed, pulverized and subjected to 5 μm-classification to removelarge particles, were mixed in accordance with the composition listed inTable 1 and stirred to disperse. Thereafter, the varnish was appliedonto a separator film (PET film) by use of a roll coater and then driedin an oven of 70° C. for 10 minutes to obtain a 20 μm-thick insulatingadhesive layer of a circuit-member connecting adhesive on the separator.

Examples 2 to 4

Varnishes of adhesive resin compositions were prepared in accordancewith the compositions listed in Table 1 in the same manner as in Example1 and through the same steps as in Example 1, and thereaftertransparency confirmation films were prepared and simultaneouslyinsulating adhesive layers of circuit-member connecting adhesives wereobtained.

Example 5

A varnish of adhesive resin composition was prepared in accordance withthe composition listed in Table 1 in the same manner as in Example 1 andthrough the same steps as in Example 1. A transparency confirmation filmwas prepared through the same steps as in Example 1 except that aluminumborate (9Al₂O₃.2B₂O₃, manufactured by Shikoku Chemicals Corporation,specific gravity: 3.0, linear expansion coefficient: 2.6×⁻⁶/° C.,refractive index: 1.62) was used, and simultaneously an insulatingadhesive layer of a circuit-member connecting adhesive.

Example 6

A varnish of adhesive resin composition containing cordierite particleswas prepared in accordance with the composition listed in Table 1 in thesame manner as in Example 1 and through the same steps as in Example 1to obtain a 45 μm-thick circuit-member connecting adhesive on aseparator film.

Subsequently, a chip (10 mm square, 280 μm in thickness) with 184 goldwire bumps (leveled, 30 μm in height) was placed on a stage of aprovisional pressure-bonding apparatus with the bump-surface facing up.The circuit-member connecting adhesive attached with a separator werecut into 12 mm-square pieces and placed over the chip such that theadhesive faces the bump-surface. Furthermore, a heat-conductive coverfilm made of silicon was placed thereon and bonded to the chip at 80° C.and 1 MPa.

After adhesion, the resin running off the outer edge of the chip wascut. The separator was peeled off from the adhesive to obtain a chipwith the adhesive. When the chip with the adhesive was observed by arecognition camera of a flip-chip bonder, an alignment mark on thecircuit surface of the chip was successfully recognized.

Alignment with a Ni/Au plated Cu printed circuit board was performed.Subsequently, heating and pressurization were performed at 180° C. and0.98 N/bump for 20 seconds to obtain a semiconductor device. Theconnection resistance of the obtained semiconductor device (176 bumpconnecting daisy chain) was 8.6Ω. It was confirmed that good connectionstate was obtained.

Furthermore, the semiconductor device was allowed to stand alone in avessel set at 30° C. and a relative humidity of 60% for 192 hours.Thereafter, an IR reflow treatment (maximum temperature: 265° C.) wasrepeated three times. No peel-off of chips and conduction failure wereobserved.

After the IR reflow treatment, the semiconductor device was furtherallowed to stand alone in a temperature cycle tester (−55° C. for 30minutes, room temperature for 5 minutes and 125° C. for 30 minutes).Connection resistance was measured in the vessel. It was confirmed thatno conduction failure occurs after 600 cycles.

Example 7

As a crosslinkable resin, epoxy resin EP1032H60 (trade name,manufactured by Japan Epoxy Resins Co., Ltd.) and a phenoxy resin YP50S(trade name, manufactured by Tohto Kasei Co., Ltd.,) having a weightaverage molecular weight of 70000 were used. As a microencapsulatedhardening agent, HX-3941HP (trade name, manufactured by Asahi KaseiCorporation) and a silane coupling agent SH6040 (trade name,manufactured by Toray Dow Corning Silicone, Co., Ltd.) were used. Thesesubstances were mixed in accordance with the composition listed in Table1 and dissolved in a toluene/ethyl acetate solvent mixture to obtain avarnish of an adhesive resin composition.

To the varnish, 50 parts by weight of cordierite particles of 1 μm inaverage particle size (2MgO.2Al₂O₃.5SiO₂, specific gravity: 2.4, linearexpansion coefficient: 1.5×10⁻⁶/° C., refractive index: 1.54), whichwere pulverized and subjected to 5 μm-classification to remove largeparticles, were mixed and stirred to disperse. Thereafter, the varnishwas applied onto a separator film (PET film) by use of a roll coater,and then dried in an oven of 70° C. for 10 minutes to obtain a 45μm-thick circuit-member connecting adhesive.

Subsequently, the adhesive was bonded to a chip attached with gold wirebumps in the same manner as in Example 6 and then connected to Au/Niplated Cu printed circuit board to obtain a semiconductor device. Theconnection resistance of the obtained semiconductor device (176 bumpconnecting daisy chain) was 8.6Ω. It was confirmed that good connectionstate was obtained.

Furthermore, the semiconductor device was allowed to stand alone in avessel set at 30° C. and a relative humidity of 60% for 192 hours.Thereafter, an IR reflow treatment (maximum temperature: 265° C.) wasrepeated three times. No peel-off of chips and conduction failure wereobserved.

After the IR reflow treatment, the semiconductor was allowed to standalone in a temperature cycle tester (−55° C. for 30 minutes, roomtemperature for 5 minutes and 125° C. for 30 minutes). Connectionresistance was measured in the vessel. It was confirmed that noconduction failure occurs after 600 cycles.

TABLE 1 Trade name or Example material name 1 2 3 4 5 6 7 NC7000 15 1515 15 15 15 — EP1032H60 — — — — — — 20 XLC-LL 15 15 15 15 15 15 —HTR-860P-3 20 20 20 20 20 20 — YP50S — — — — — — 35 HX-3941HP 50 50 5050 50 50 45 SH6040  1  1  1  1  1  1  1 Cordierite 100  75 50 25 — 50 50Aluminum borate — — — — 50 — — (Unit: part by weight)

Example 8

Transparency confirmation film having a composition listed in Table 2was prepared in the same procedures as mentioned above except thatconductive particles of 3 μm in average particle size, which were formedby providing a 0.2 μm-thick nickel layer on the surface of particleshaving a polystyrene core and providing a 0.04 μm thick gold layeroutside the nickel layer, were further mixed with the insulatingadhesive layer obtained in Example 1, and a 5 μm-thick particle layerfor a circuit-member connecting adhesive was obtained on the separator.The insulating adhesive layer and the particle layer were bonded by alaminator to obtain a 25 μm-thick circuit-member connecting anisotropicconductive adhesive.

Examples 9 to 11

The same steps as in Example 8 were repeated except that, to theinsulating adhesive layers obtained in Examples 2 to 4, further a 0.2μm-thick nickel layer was provided on the surface of particles having apolystyrene core. As a result, a 25 μm-thick circuit-member connectinganisotropic conductive adhesives were obtained.

Example 12

The same steps as in Example 8 were repeated except that, to theinsulating adhesive layers obtained in Example 5, a 0.2 μm-thick nickellayer was provided on the surface of particles having a polystyrenecore. As a result, a 25 μm-thick circuit-member connecting anisotropicconductive adhesive was obtained.

TABLE 2 Trade name or Example material name 8 9 10 11 12 NC7000 15 15 1515 15 EP1032H60 — — — — — XLC-LL 15 15 15 15 15 HTR-860P-3 20 20 20 2020 YP50S — — — — — HX-3941HP 50 50 50 50 50 SH6040  1  1  1  1  1Cordierite 100  75 50 25 — Aluminum borate — — — — 50 Conductive 5 vol %5 vol % 5 vol % 5 vol % 5 vol % particles (Unit: part by weight)

Comparative Example 1

As a crosslinkable resin, an epoxy resin NC7000 (trade name,manufactured by Nippon Kayaku Co., Ltd.) was used. As a hardening agentreacting with the crosslinkable resin, phenol-aralkyl resin XLC-LL(trade name, manufactured by Mitsui Chemicals Inc.) was used. As acopolymerizable resin having a molecular weight of 1 million or less anda Tg of 40° C. or less and containing at least one functional groupreactive to the crosslinkable resin in a side chain, an epoxy-groupcontaining acrylic rubber HTR-860-3 (trade name, manufactured by NagaseChemteX Corporation, weight average molecular weight: 0.3 million) wasused. As microencapsulated hardening agent, HX-3941HP (trade name,manufactured by Asahi Kasei Corporation) and a silane coupling agentSH6040 (trade name, manufactured by Toray Dow Corning Silicone, Co.,Ltd.) were used. The aforementioned substances were dissolved in atoluene/ethyl acetate solvent mixture in accordance with the compositionlisted in Table 3 to obtain a varnish of an adhesive resin composition.

To the varnish, silica particles SE2050 of 0.5 μm in average particlesize (trade name, manufactured by Admatechs Co., Ltd., specific gravity:2.22, linear expansion coefficient: 5×10⁻⁷/° C., refractive index:1.46), which were subjected to 5 μm-classification to remove largeparticles, were mixed in accordance with the composition listed in Table3 and stirred to disperse. Thereafter, the varnish was applied onto aseparator film (PET film) by use of a roll coater and then dried in anoven of 70° C. for 10 minutes to obtain a 25 μm-thick transparencyconfirmation film on the separator.

As shown in FIG. 10, it was difficult to recognize an image on the rearside of the obtained transparency confirmation film through the film.

Subsequently, the varnish was weighed and silica particles SE2050 havingan average particle size of 0.5 μm were mixed in accordance with thecomposition listed in Table 3 and stirred to disperse. Thereafter, thevarnish was applied onto a separator film (PET film) by use of a rollcoater and then dried in an oven of 70° C. for 10 minutes to obtain a 20μm-thick insulating adhesive layer of a circuit-member connectingadhesive on a separator.

Comparative Example 2

A varnish for an adhesive resin composition was prepared in accordancewith the composition listed in Table 3 in the same manner as inComparative Example 1 and through the same steps as in ComparativeExample 1. Thereafter, a transparency confirmation film was prepared andsimultaneously an insulating adhesive layer of a circuit-memberconnecting adhesive was obtained.

Comparative Example 3

A varnish for an adhesive resin composition was prepared in accordancewith the composition listed in Table 3 in the same manner as inComparative Examples 1 and 2 and through the same steps as inComparative Example 1. Thereafter, the varnish was applied onto aseparator film (PET film) by use of a roll coater and then dried in anoven of 70° C. for 10 minutes to obtain a 20 μm-thick insulatingadhesive layer of a circuit-member connecting adhesive on the separator.

Comparative Example 4

As a crosslinkable resin, an epoxy resin NC7000 (trade name,manufactured by Nippon Kayaku Co., Ltd.) was used. As a copolymerizableresin having a molecular weight of 1 million or less and a Tg of 40° C.or less and containing at least one functional group reactive to thecrosslinkable resin in a side chain, an epoxy-group containing acrylicrubber HTR-860P-3 (trade name, manufactured by Nagase ChemteXCorporation, weight average molecular weight: 0.3 million) was used. Asa hardening agent, 2PHZ (trade name, manufactured by Shikoku ChemicalsCorporation), a silane coupling agent SH6062 (trade name, manufacturedby Dow Corning Toray, Co., Ltd.), A1160 (trade name, manufactured byNihon Unicar), and silica microparticle Aerosil (registered trade mark)R805 (trade name, manufactured by Japan Aerosil, primary particle size:17 nm) were used. The aforementioned substances were dissolved in atoluene/ethyl acetate solvent mixture in accordance with the compositionlisted in Table 3 to obtain a varnish of an adhesive resin composition.

After the varnish mixture was stirred to disperse, it was applied onto aseparator film (PET film) by a roll coater and then dried in an oven of70° C. for 10 minutes to obtain a 25 μm-thick transparency confirmationfilm on the separator film. Subsequently, the same steps as inComparative Example 1 were repeated to obtain a 20 μm-thick insulatingadhesive layer of a circuit-member connecting adhesive on the separator.

Comparative Example 5

As a crosslinkable resin, an epoxy resin NC7000 (trade name,manufactured by Nippon Kayaku Co., Ltd.) was used. As a hardening agentreacting with the crosslinkable resin, phenol-aralkyl resin XLC-LL(trade name, manufactured by Mitsui Chemicals Inc.) was used. In placeof the microencapsulated hardening agent, liquid epoxy resin Epicoat 828(trade name, manufactured by Japan Epoxy Resins Co., Ltd.) and ahardening agent 2PHZ (trade name, manufactured by Shikoku ChemicalsCorporation) were used. As a copolymerizable resin having a molecularweight of 1 million or less and a Tg of 40° C. or less and containing atleast one functional group reactive to the crosslinkable resin in a sidechain, an epoxy-group containing acrylic rubber HTR-860P-3 (trade name,manufactured by Nagase ChemteX Corporation, weight average molecularweight: 0.3 million), a silane coupling agent SH6040 (trade name,manufactured by Toray Dow Corning Silicone, Co., Ltd.) and silicamicroparticle Aerosil (registered trade mark) R805 (trade name,manufactured by Japan Aerosil, primary particle size: 17 nm) were used.The aforementioned substances were dissolved in a toluene/ethyl acetatesolvent mixture in accordance with the composition listed in Table 3 toobtain a varnish of an adhesive resin composition.

After the varnish mixture was stirred to disperse, it was applied onto aseparator film (PET film) by a roll coater and then dried in an oven of70° C. for 10 minutes to obtain a 25 μm-thick transparency confirmationfilm on the separator film. Subsequently, the same steps as inComparative Example 1 were repeated to obtain a 20 μm-thick insulatingadhesive layer of a circuit-member connecting adhesive.

Comparative Example 6

A varnish for an adhesive resin composition was prepared in accordancewith the composition listed in Table 3 in the same manner as in Example1 except that the cordierite particles of Example 1 were replaced bysilica microparticle Aerosil (registered trade mark) R805 (trade name,manufactured by Japan Aerosil, primary particle size: 17 nm).Thereafter, a transparency confirmation film was prepared andsimultaneously an insulating adhesive layer of a circuit-memberconnecting adhesive was obtained.

TABLE 3 Trade name or Comparative Example material name 1 2 3 4 5 6NC7000  15 15 15 50 15 15 Epicoat 828 — — — — 30 — XLC-LL  15 15 15 — 1515 HTR-860P-3  20 20 20 50 20 20 HX-3941HP  50 50 50 — — 50 2PHZ — — — 1.25  1.25 — SH6040  1  1  1 —  1  1 SH6062 — — —  0.75 — — A1160 — — — 1.5 — — SE2050 100 25 — — — — R805 — — — 15 15 15 (Unit: part byweight)

Comparative Examples 7 to 12

Transparency confirmation films having compositions listed in Table 2were prepared in the same procedures as mentioned above except thatconductive particles of 3 μm in average particle size, which were formedby providing a 0.2 μm-thick nickel layer on the surface of particleshaving a polystyrene core and providing a 0.04 μm thick gold layeroutside the nickel layer, were mixed with the insulating adhesive layersobtained in Comparative Example 1 to 6 and a 5 μm-thick particle layerof a circuit-member connecting adhesive was obtained on the transparencyconfirmation films. The insulating adhesive layer and the particle layerwere bonded by a laminator to obtain a 25 μm-thick circuit-memberconnecting anisotropic conductive adhesive.

TABLE 4 Trade name or Comparative Example material name 7 8 9 10 11 12NC7000 15 15 15 50 15 15 Epicoat 828 — — — — 30 — XLC-LL 15 15 15 — 1515 HTR-860P-3 20 20 20 50 20 20 HX-3941HP 50 50 50 — — 50 2PHZ — — —1.25 1.25 — SH6040  1  1  1 — 1  1 SH6062 — — — 0.75 — — A1160 — — — 1.5— — SE2050 100  25 — — — — R805 — — — 15 15 15 Conductive 5 vol % 5 vol% 5 vol % 5 vol % 5 vol % 5 vol % particles (Unit: part by weight)

(Laminate of Semiconductor Wafer/Circuit-Member ConnectingAdhesive/Dicing Tape)

An adsorption stage of a die attach film mounter manufactured by JCMCo., Ltd. was heated to 80° C. Thereafter, a semiconductor wafer of6-inch in diameter and 150 μm in thickness having gold-plated bumpsformed thereon were mounted on the adsorption stage with a bump-sidesurface facing up.

The circuit-member connecting adhesives of Examples 1 to 5 andComparative Examples 1 to 6 attached with separators were cut intopieces having a dimension of 200 mm×200 mm, which were laminated with aninsulating adhesive layer side facing the bump side of the semiconductorwafer by pressing by the bonding roller of the die attach mounter froman end of the semiconductor wafer so as not to include air.

After the lamination, the portion of the adhesive running off the outeredge of the wafer was cut away. After cutting, the separator was peeledoff and then a laminate of the wafer and the circuit-member connectingadhesive (from which the separator was already peeled off) was mountedon the adsorption stage of the die attach film mounter set at 40° C.with the surface attached with the adhesive facing up. Furthermore, adicing frame for a 12-inch wafer was arranged along the circumference ofthe wafer.

UV-curable dicing tape UC-334EP-110 (trade name, manufactured by TheFurukawa Electric Co., Ltd.) was laminated with a sticky surface facingthe semiconductor wafer by pressing by the bonding roller of the dieattach mounter from an end of the dicing frame so as not to include air.

After the lamination, the dicing tape was cut in the middle between theouter circumference and the inner circumference of the dicing frame toobtain a laminate of a semiconductor wafer/circuit-member connectingadhesive/dicing tape fixed on the dicing frame.

(Dicing)

The laminate of a semiconductor/circuit-member connectingadhesive/dicing tape fixed on the dicing frame was mounted on afull-automatic dicing saw DFD6361 (trade name) manufactured by DiscoCorporation with the back-grind surface of the semiconductor waferfacing up. Alignment of a scribe line was performed through the wafer byuse of an IR camera.

In the first stage, cut was made to 100 μm from the back-grind surface.The remaining wafer, circuit-member connecting adhesive and the part ofthe dicing tape were cut at intervals of 15.1 mm in the long sidedirection and at intervals of 1.6 mm in the short side direction. Aftercutting, washing was performed and moisture was blown out by blowing andthen UV rays were applied to the dicing tape. Thereafter, the dicingtape was pushed up toward the semiconductor wafer to obtainsemiconductor chips of 15.1 mm×1.6 mm having a circuit-member connectingadhesive formed on the bump side.

(Pressure-Bonding)

The chip was suctioned in such a manner that the back-grind surface ofthe semiconductor chip with the circuit-member connecting adhesive facesthe adsorption head of an ultrasonic flip-chip bonder SH-50 MP (tradename, manufactured by Altecs Co., Ltd.). The chips was irradiated withlight using a halogen light source manufactured by Moritex Corporationand a light guide from the circuit-member connecting adhesive side torecognize an alignment mark formed on the surface of the semiconductorchip. In this way, alignment was performed.

On the other hand, an alignment mark formed of ITO on a board having1400 angstrom-thick indium-tin oxide (ITO) film electrodes formed on a0.7 mm-thick non-alkali glass, was recognized and aligned. Thereafter, achip was pressed at 0.5 MPa for one second on the glass board withoutheating. In this manner, a semiconductor chip was provisionally fixed onthe glass board with the circuit-member connecting adhesive interposedbetween them.

Subsequently, the chip was pressed on the glass under the conditions:temperature: 210° C. and pressure: 50 MPa, for 5 seconds andsimultaneously the adhesive was hardened. In this manner, bondingbetween the bump and the ITO electrodes and adhesion between the chipand the glass board were completed. After the pressure-bonding, aconnection resistance value was checked.

After a connection resistance value was checked, the semiconductorchip-glass board united body was placed in a high-temperature/humidityapparatus (60° C. and 90% RH) or a cycle tester (−40° C., 15 minutes and100° C., 15 minutes) in order to check the connection reliability of thecircuit-member connecting adhesive. After a certain time period, achange in connection resistance was measured.

(Measurement of Linear Expansion Coefficient)

Each of the circuit-member connecting adhesives according to Examplesand Comparative Examples was placed together with a separator in an ovenset at 180° C. for 3 hours to perform a heat hardening treatment. Afterheat hardening, the film was peeled off from the separator and cut intopieces of 30 mm×2 mm in size. Using TMA/SS6100 (trade name, manufacturedby Seiko Instruments Inc. (after the distance of chucks was set at 20mm)), thermo mechanical analysis was performed in the conditions:measurement temperature range: 20° C. to 300° C., temperature raisingrate: 5° C./min, loading condition: 0.5 MPa-pressure/sectional area, inaccordance with a tensile test mode to obtain a linear expansioncoefficient.

(Measurement of Reactivity)

Each of the circuit-member connecting adhesives according to Examplesand Comparative Examples (2 to 10 mg) was weighed in an aluminummeasurement container and measured for a calorific value by DSC Pylis 1(trade name) manufactured by Perkin Elmer, Inc in the range from 30 to300° C., at a temperature raising rate of 20° C./min. This is regardedas an initial calorific value.

Subsequently, the temperature of the heat head of a thermocompressionbonding apparatus was set at a temperature such that temperature reached180° C. in 20 seconds after the temperature was confirmed by athermocouple sandwiched between separators. The circuit-memberconnecting adhesive sandwiched between separators was heated for 20seconds by the heating head set at the conditions. In this way, a filmto which the same heat treatment as a thermocompression bonding processwas applied was obtained. After the heat treatment, the film (2 to 10mg) was weighed and placed in an aluminum measurement container andsubjected to calorific value measurement performed by DSC from 30 to300° C. at a temperature increased rate of 20° C./min. This is regardedas a calorific value after heating. A reactivity (%) was calculated fromthe calorific values obtained, in accordance with the following formula:

(Initial calorific value-calorific value after heating)/(initialcalorific value)×100.

Properties of the circuit-member connecting adhesives, morespecifically, parallel transmittance, linear expansion coefficient afterhardening, whether a recognition mark is observed or not by a flip-chipbonder, reactivity and further a connection resistance value afterpressure-bonding, and a connection resistance value after thereliability test are shown in Tables 5 and 6 with respect to each ofExamples and Comparative Examples.

TABLE 5 Example Item 1 2 3 4 5 6 7 Parallel 18 25 29 33 32 29 18transmittance (%) Linear expansion 38 48 58 69 26 58 35 coefficient(40-100° C.) (×10⁻⁶/° C.) Recognition of chip Recognized RecognizedRecognized Recognized Recognized Recognized Recognized alignment markReactivity (%) 89 88 89 86 89 89 92 Connection 0.2 0.4 0.5 4.7 1.6 — —resistance after pressure-bonding (Ω) Connection 48 60 220 330 150 — —resistance after high- temperature/humidity test (200 h) (Ω) Connection20 40 100 200 60 — — resistance after temperature cycle test (200cycles) (Ω)

TABLE 6 Comparative Example Item 1 2 3 4 5 6 Parallel  2  7 60  15  4547 transmittance (%) Linear expansion 42 82 88 170 102 87 coefficient(40-100° C.) (×10⁻⁶/° C.) Recognition of chip Not Not RecognizedRecognized Recognized Recognized alignment mark recognized recognizedReactivity (%) 88 86 88  1  0 86 Connection Conductive Conductive 10.2Conductive Conductive  0.7 resistance after failure failure failurefailure pressure-bonding (Ω) Connection — — Conductive — — Conductiveresistance after high- failure failure temperature/humidity test (200 h)(Ω) Connection — — Conductive — — Conductive resistance after failurefailure temperature cycle test (200 cycles) (Ω)

As shown in Table 5, the circuit-member connecting adhesives employingcordierite or aluminum borate having a refractive index of 1.5 to 1.7 ascomposite oxide particles have a parallel transmittance of 15% or moreand a turbidity of 85% or less. Therefore, it is possible to recognize arecognition mark on a chip circuit surface through the adhesive by useof a recognition system of a flip-chip bonder. Since composite oxideparticles having a low thermal expansion coefficient are contained, thelinear expansion coefficient after hardening is reduced. In addition, inthe connection reliability test, the reactivity reaches 80% or more inthe heating conditions during a thermocompression bonding process whereno conductive failure occurs. It is confirmed that a low connectionresistance can be stably shown. Therefore, it is apparent that they areexcellent adhesives for flip-chip connection.

On the other hand, as shown in Table 5, in Comparative Examples 1 and 2,the turbidities are large and the parallel transmittances are low sincesilica having a refractive index of 1.46 is used. A recognitionoperation cannot be performed by a flip-chip bonder and alignment cannotbe performed. As a result, the semiconductor apparatus cannot ensureinitial conductivity. In Comparative Example 3, since composite oxideparticles are not added, a linear expansion coefficient is large,causing conductive failure. In Comparative Examples 4 and 5, thereactivity is low and rapid hardening cannot be made. As a result,conductive failure occurs in the semiconductor device. Furthermore, inComparative Example 6, since Aerosil (registered trade mark) has a largespecific surface area, the amount that can be blended to a resin is low.Because of the low content, it is difficult to reduce a linear expansioncoefficient. As a result, disadvantages such as conductive failureinevitably occur.

INDUSTRIAL APPLICABILITY

The film-type adhesive for connecting circuit members of the presentinvention can provide a semiconductor chip with an adhesive for use in apreset underfill method capable of dealing with narrow-pitch andnarrow-gap tendency without causing contamination during a dicingprocess and capable of peeling off from a dicing tape after dicing;furthermore can be used as a rapid-hardening circuit-member connectingadhesive for applying to a wafer capable of attaining not onlytransparency for realizing accurate alignment of adhesive chips but alsohigh connection reliability due to a low thermal expansion coefficient.

1. An adhesive for connecting circuit members, which is interposedbetween a semiconductor chip having protruding connecting terminals anda board having wiring patterns formed thereon for electricallyconnecting the connecting terminals and the wiring patterns facing eachother and bonding the semiconductor chip and the board by applyingpressure/heat, the adhesive comprising (a) a resin compositioncomprising a thermoplastic resin, a crosslinkable resin and a hardeningagent for forming a crosslink structure of the crosslinkable resin; and(b) composite oxide particles dispersed in the resin composition,wherein the composite oxide particles have a refractive index of 1.5 to1.7 and are particles formed of a composite oxide comprising two or moretypes of metal elements.
 2. The adhesive for connecting circuit membersaccording to claim 1, wherein a refractive index difference between theresin composition and the composite oxide particles falls within ±0.06.3. (canceled)
 4. The adhesive for connecting circuit members accordingto claim 1, wherein the composite oxide particles are particles formedof at least one type of metal element selected from aluminum andmagnesium, and an oxide comprising a metal element except the metalelements or a metalloid element.
 5. The adhesive for connecting circuitmembers according to claim 4, wherein the metalloid element is siliconand/or boron.
 6. The adhesive for connecting circuit members accordingto claim 1, wherein the composite oxide particles are particlescomprising a composite oxide having a specific gravity of 4 or less. 7.(canceled)
 8. The adhesive for connecting circuit members according toclaim 1, wherein the composite oxide particles are composite oxideparticles having an average particle size of 15 μm or less. 9.(canceled)
 10. The adhesive for connecting circuit members according toclaim 1, wherein a visible-light parallel transmittance in an unhardenedstate is 15 to 100%.
 11. The adhesive for connecting circuit membersaccording to any one of claim 1, wherein a reactivity obtained afterheating at 180° C. for 20 seconds and measured by a differentialscanning calorimeter is 80% or more.
 12. The adhesive for connectingcircuit members according to claim 1, wherein a linear expansioncoefficient measured at 40° C. to 100° C. after hardening is 70×10-6° C.or less.
 13. The adhesive for connecting circuit members according toclaim 1, wherein the thermoplastic resin is a copolymerizable resinhaving a weight average molecular weight of 1 million or less and aglass transition temperature of 40° C. or less, and having a reactivefunctional group with the crosslinkable resin in a side chain, whereinthe crosslinkable resin is an epoxy resin, and wherein the hardeningagent is a microencapsulated hardening agent.
 14. The adhesive forconnecting circuit members according to claim 1, the adhesive furthercomprising (c) conductive particles having an average particle size of 3to 5 μm dispersed therein.
 15. A semiconductor device comprising: (i) anelectronic component comprising a semiconductor chip having connectingterminals; and (ii) a board having wiring patterns formed thereon areelectrically connected by the adhesive for connecting circuit membersaccording to claim 1.